1. Field of the Invention
The present invention relates to retained earth structure in general and in particular to a retained earth structure comprising a plurality of interlocked facing wall modules connected to elongated wire mesh reinforcing panels by means of a novel clevis and bolt assembly.
2. Description of the Prior Art
A retained earth structure comprises a wall for retaining earth and/or other backfill material placed behind the wall. Elongated members extend from various locations on the back surface of the wall into the backfill material. The elongated members are captured by the backfill material and prevent the wall from buckling outwardly.
The wall may comprise a uniform, unbroken expanse of concrete or the like which is poured on site. Alternatively, the wall may comprise a plurality of interlocking precast modules or wall members which are assembled on site.
The use of precast modules tends to be less expensive than on-site poured concrete because the installation and removal of the forms required when concrete is poured on site and the transportation to and pouring of large amounts of concrete on site are generally not required. Moreover, the amount of labor required for assembling the modules is generally less than that required for poured concrete walls.
Initially, the elongated members used for preventing the outward buckling of the wall in retained earth structures comprised elongated straps of material having a generally rectangular cross-section. Outward movement of the wall and the straps from the backfill material was prevented by means of friction between the backfill material and the straps.
Several methods and apparatus have been provided in the past for attachaing the strap members to individual wall modules. For example, in U.S. Pat. No. 3,686,873, there is disclosed a number of structures comprising a plurality of individual strap members which are attached to a plurality of wall modules. In one such structure one or more U-shaped members having widely spaced legs are anchored in each one of the wall modules. The ends of each leg of each U-shaped member extends beyond the back surface of the module. A bolt and nut assembly is used to attach one end of each strap member to the end of each of the legs of each of the U-shaped members.
In another one of the structures disclosed in the patent, one or more ring-shaped members are anchored in each of the modules and one end of each strap member is passed through the ring-shaped member, folded back on itself and bolted or riveted to an underlying section thereof.
In still another one of the structures disclosed in the patent, the end of each strap member is attached to the modules by passing a rod or pin used for interlockng the modules together through a hole provided therefor in the end of the strap member.
In U.S. Pat. No. 4,449,857, there is disclosed a structure comprising a plurality of wire mesh panels which are attached to a plurality of wall modules by means of threaded female fittings anchored in the wall modules and threaded male fittings movably mounted to the end of each elongated wire in the wire mesh panel.
In each panel there is provided a plurality of four to six elongated parallel 1/2" to 3/8" wires which are spaced six inches apart and interconnected by crossbars which are welded perpendicularly to the wires on 24-inch centers.
The advantage that the wire mesh panels have over the previously described straps is that, in addition to friction forces, outward movement of the panels and the wall modules attached thereto is further restrained by the crossbars which engage the backfill material bearing downwardly thereon.
Disadvantages of the prior known wire mesh panel structures are that the threaded female and male fittings used for attaching the wire mesh panels to the wall modules are relatively expensive to make; the threading of each male fitting into each female fitting during installation is relatively time consuming; and the strength of each attachment corresponds to the relatively limited strength of an enlarged protuberance located at the end of each wire in the panel for retaining the male part of the fitting.